Copying materials for photographic reflection printing

ABSTRACT

A copying material for photographic reflection printing and adapted for ultraviolet transmittance printing, in which a light sensitive silver halide emulsion layer is provided on a thermoplastic synthetic paper having a specular gloss of more than 10 percent, an opacity of 70 to 90 percent and an average transmittance of ultraviolet rays in the wave-length range of 320 to 450 m Mu of more than 5 percent.

United States Patent '91 Tani et al.

[ 1 Jan. 9, 1973 [54] COPYING MATERIALS FOR PI-IOTOGRAPHIC REFLECTION PRINTING [75] Inventors: Kaneyasu Tani, Tokyo; Shlro Kawazoe, Kawaguchi; Mikio Eto;

Sunao Okamoto, both of Tokyo; Tamotsu Fujino, Tokorozawa, all of Japan [731 Assignees: Japan Synthetic Paper Company Ltd. Oriental Photo Industrial Co., Ltd., Tokyo, Japan 22 Filed: May 12, 1970 21 Appl. No.: 36,658

[30] I Foreign Application Priority Data Mayl3,l969 Japan..; ..44/3672l [52] U.S. Cl. ..96/87 R, 96/47, 117/47 A [51] Int. CL. ..G03c 1/76 Primary Examiner-Ronald H. Smith AttorneyWoodhams, Blanchard and Flynn [57] ABSTRACT A copying material for photographic reflection printing and adapted for ultraviolet transmittance printing, in which a light sensitive silver halide emulsion layer is provided on a thermoplastic synthetic paper having a specular gloss of more than 10 percent, an opacity of 70 to 90 percent and an average transmittance of ultraviolet rays in the wave-length range of 320 to 450 mg. of more than 5 percent.

4 Claims, 1 Drawing Figure COPYING MATERIALS FOR PHOTOGRAPIIIC REFLECTION PRINTING BACKGROUND OF THE INVENTION ing materials for reflection printing comprise a photographic paper base prepared 'by coating white pigments, such as barium sulfate or titanium dioxide on a wood free paper and a light sensitive silver halide emulsion layer is coated thereon. Although on such a copying material there can be 'formed'a silver image having an excellent image-quality by means ofreflection printing, the copying material has disadvantages, for example, it is difficult to use such'an image-formed material as an intermediate original for ultraviolet transmittance printing in order to print the image on an ultraviolet sensitive copying material, such as a light sensitive diazo paper or a light sensitive resin coated plate, because the transmittance to ultraviolet of saidcopying material is reduced by virtue of the ultraviolet-absorbing effects of thepaper fibers and white pigments.

It is also well known that such absorbing effects cause difficulties in printing on a copying material which is sensitive to near ultravioletrays having wavelengths from 320to 450 mplby means of transmittance printing.

On the other hand, it is further well'known that a copying material prepared'by applying a light sensitive silver halide emulsion to a photographic paper base which is not coated with anywhite pigmentin order to increase'the transmittance ofultraviolet rays, has prac-.

tical disadvantages, for e'xample, the copying material thus prepared gives a silver image of a remarkably inferior quality, because the surface of such a photographic paper base is very rough and the'scattering of light, which will cause a reduction of the resolving power of the light sensitive material on reflection printing, will appear as the result of insufficient adhesion between the emulsion layer and the surface of the paper base. Accordingly, it has been impossible to achieve simultaneously both the requirements of excellent image-quality-of an image formed by reflection printing and good transmittance of ultraviolet rays in printing on a conventional 'ultraviolebsensitive copying materialby transmittance printing.

A method has been provided in which reflecting property necessary for reflection printing of a copying material was improved by coating finely divided particles of white pigment, which particles are soluble in a developing treatment solution. The transmittance of ultraviolet rays of the copying material after the reflection printing was increased by dissolving or decomposing the pigment particles during the developing treatment, thereby removing them from the copying material. Such a method is undesirable because of the remarkable contamination of the developing solution caused by dissolving or decomposing the pigment particles therein.

SUMMARY OF THE INVENTION The object of the present invention is to provide a copying material which does not possess the foregoing disadvantages, that is, it has a high transmittance to ultraviolet rays and gives a reproduced image having excellent image-quality by means of reflection printing.

We have found that this object can be attained by selecting the material to be used as the support in a copying material and by imparting properties suitable for reflection printing to the material by subjecting it to a physical or chemical treatment.

In this invention, the properties suitable for reflection printing refer to the opacity and the smoothness of the support. Namely, in the case of using a transparent support, faithful reproduction cannot be expected, because the light which has passed through a light sensitive layer and has been reflected at the surface of the first original causes halation at the boundary of a light sensitive layer and a support reflection printing,

whereby the light is scattered so as not to form a sharp image on the light sensitive layer. In order to obtain a good image reproduction, the material to be used as the support in a copying material must have an opacity of more than percent.

However, because an excessively high opacity will cause prolongation of the time for reflection printing, an opacity within the range of 70 to 95 percent, preferably to '85 percent, is desirable. The measurement-of the opacity is carried out by the method of Japan Industrial Standard 'No. .llSP-8l38. According to this method,the reflection rate of a green light in case a white standard plate is used and the reflection -rate of the green-lig'ht-in case a'black'standard plate is used are measured by means of a Hunter Brightness meter and the opacity of the sample is represented by the ratio'between these reflection rates.

As' another property necessary for reflection printing,'the smoothness of the surface of the support is important. This will influence the smoothness of the surface of a light sensitive emulsion layer coated on the support. When thesmoothness of the surface of the support is small, the light used for reflection printing will be scattered and an image of good quality can not be obtained.

The smoothness of the surface of a support can be represented by the specular gloss measured by the method of Japan Industrial Standard No. JIS-Z-874l. Accordingto this method, the specular gloss of a sample can be'measured by means of a specular gloss meter, which has been adjusted first by using a black glass plane having a predetermined refractive index (n L567) as the first standard surface and next by using a white tile surface as the second standard surface, then the measurement being made by replacing it with the sample. The specular gloss values mentioned in the specification and claims have been obtained under the condition of a specular reflection angle of 60. According to the present invention, the specular gloss of the support, at a specular reflection angle of 60, should be more than 10 percent.

Further, as a property necessary for transmittance printing by ultraviolet rays, the transmittance to ultraviolet rays of the support should be sufficiently great. That is to say, the average transmittance to near ultraviolet rays in the wave length range between 320 and 450 myishould be more than 5 percent, more preferably more than 10 percent. In this case, the transmittance of ultraviolet rays is shown by the transmittance measured by a spectrophotometer.

Further, an additional object of the present invention is to improve the dimensional stability of the copying material. The copying material according to the invention has an improved dimensional stability to the developing treatment as compared with a conventional copying paper in which a paper is used as a support. Such dimensional stability is considered as an advantageous property when the material is used as an intermediate original.

According to the present invention, there is provided a novel copying material for photographic reflection printing and adapted for ultraviolet transmittance printing, which comprises a light sensitive silver halide emulsion layer coated on a thermoplastic synthetic paper having a specular gloss of more than l percent, preferably more than 30 percent, an opacity of 70 to 90 percent, preferably 75 to 85'percent, and an average transmittance of ultraviolet rays in the wave-length range of 320 to 450 mp. of more than 5 percent, preferably more than percent. The thermoplastic synthetic'paper to beused as the support for the copying material can be prepared by treating at least the surface of a thermoplastic synthetic resin film, the absorption of which to near ultraviolet rays is low, suchas polystyrene, polyvinylchloride, polypropylene, polyethylene terephthalate and polycarbonate, by means of an appropriate physical or chemical process so as to form a micro porous layer on the surface of the film.

As a process for effecting such physical or chemical treatment, the surface of a thermoplastic synthetic resin film, such as mentioned above, is treated, after the film has been formed, with a solvent or a swelling agent, the swelled layer thus formed is dried suitably and then it is treated with a non-solvent or a nonswelling agent, which is miscible with the above solvent or swelling agent, to coagulate the swollen layer and then dried completely.

As another treatment process, a thermoplastic synthetic resin solution is cast on an article having a mirror finish planar surface in order to form a film, thereon the cast layer is dried incompletely and contacted with a liquid which is not miscible with said synthetic resin but [is miscible with said solvent to coagulate the cast layer into the shape of a film, then this coagulated film is biaxially stretched under heating and dried under tension.

As another treatment process, a synthetic resin film is dipped in a swelling agent and swelled, then pressed on a metal plate having a mirror finish planar surface by rolling, dipped in a non-swelling solvent to coagulate the swelled layer and dried.

As another treatment process, the surface of a foamed film is treated with a solvent to dissolve the surface layer so as to increase the gloss of the film.

By means of one of these treatment processes, a micro porous layer can be provided on the surface of the treated thermoplastic synthetic resin film and a thermoplastic resin paper having the above properties required as a support for the copying material according to the present invention can be obtained.

Generally, an opaque film is obtained by swelling the surface of a high polymer film and then coagulating it. In this case, ifthe swelled layer is dried to increase the density of the swelled layer formed on the film surface during the intermediate step between the swelling and coagulating treatments or the swelled layer is east on an article having a mirror finish planar surface, a gloss is produced on the surface of the layer. This intermediate drying may be a natural drying of a forced drying, but it is particularly essential to stop the drying at the point when a wet condition on the surface is maintained without drying it completely. The gloss can be controlled by the degree of this intermediate drying. Also, in case the film is cast on an article having a mirror plane finish planar surface, the gloss can be controlled by the pressure of the casting or the state of the mirror plane finish.

On the other hand, the opacity can be controlled by the selection of the swelling agent and non-swelling agent to be used or the temperature of the treating solution, since the opacity is determined by the conditions of the above swelling and coagulating steps and not by those of the intermediate drying.

According to the present invention, because there is used a support having specular gloss and opacity values within the limited ranges as stated above, prepared by subjecting the surface thereof to a chemical or physical treatment without incorporating therein any white pigments, there is obtained, a desirable copying material which not only has a high rcsolving-power-to afford an excellent image-quality on a reproduced image but also is applicable as an intermediate original in transmittance printing by ultraviolet rays and also has an excellent dimensional stability.

The micro porous layer formed by such a method as mentioned above may be provided on one surface of the support or both surfaces thereof. Further, the whole support can-be comprised of a micro porous film. When micro porous layers are provided on both surfaces of the support, it is also possible after the reflection printing to increase the transparency of the support to visible light by applying a suitable solvent or pressure to the surface not having an emulsion layer provided thereon.

ln coating a light sensitive silver halide emulsion on the surface of a support prepared by such processes as hesion between the emulsion layer and the support is remarkably improved.

Furthermore, it is also possible to apply to the support a chemical treatment, e.g., the application of an oxidizingagent such as potassium permanganate or concentrated sulfuric acid to make the surface thereof hydrophilic and a combination of-such physical treatment and chemical treatment may be performed.

As the light sensitive silver halide emulsion to be used in the present invention, there can be used any light sensitive emulsion containing silver chloride, silver chlorobromide, silver bromide, silver iodobromide or silver iodochlorobromide and the light sensitive emulsion may or may not contain a developing agent or a sensitizing dye.

BRIEF DESCRIPTION OF DRAWING The accompanying drawing is a graph showing the spectral transmittance of a conventional baryta-coated photographic paper base (80 g/m and that of a synthetic paper (80 g/m have a micro porous layer on the surface thereof according to the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS The present invention will be further illustrated with reference to the following examples. However, the invention is not limited to those examples and it include the various modifications within the scope of the claims mentioned below.

EXAMPLE l l. By applying on a wood free paper having a thickness of 80 microns a coating composition comprising Rutile-type titanium dioxide dispersed in a water-soluble binder such as casein to yield a dry thickness of microns, a sheet material for a support having a specular gloss of 12 percent, an opacity to visible light of 80 percent and an average transmittance of near ultraviolet rays within the'wave-length range from 320 to 450 mp. of 1.5 percent was obtained. On the resulting support, a conventionally prepared gelatino silver halide emulsion containing 30 percent by weight of silver bromide and 70 percent by weight of silver chloride was applied at the rate of l.() g of silver per square meter of the surface of the support, after 5 ml of 10 percent (by weight) aqueous chromium alum solution and 1 ml of l0 percent (by weight) aqueous saponin solution have been previously added to the emulsion. The light sensitive copying material thus prepared is hereinafter referred to as Sample A.

2. On a wood free paper having a thickness of 85 microns as a support, not containing any pigments and having a specular gloss of 3.0 percent, an opacity to a visible light of 60 percent and an average transmittance to near ultraviolet rays within the wave-length range from 320 to 450 mg. was applied an emulsion prepared by the same method. The resulting lightsensitive copying material is hereinafter referred to as Sample B.

3. By immersing a biaxially stretched high impact polystyrene film having a thickness of 75 p. produced by Mitsubishi Monsanto Co., Ltd.) into a swelling bath consisting of 95 parts by weight of methyl-iso-butyl ketone as a swelling agent and -5 parts by weight of methyl alcohol at 30C for 3 seconds to form micro porous layers on the both surfaces of the film, thereafter drying the film in the air at C for 6 seconds, immersing again the resulting film into a bath of methyl alcohol as a non-swelling agent at C for 40 seconds to coagulate the layers and followed by drying at room temperature, a paper-like material having a specular gloss of 40 percent, an opacity of 85 percent and an average transmittance to near ultraviolet rays within the wave-length range from 320 to 450 mg. of 10 percent was obtained. The resulting paper-like material was treated with a corona discharge treatment under a current of 800 mA and a output of 400W by using a LEPEL HFG ll-type high frequency spark generator manufactured by LEPEL High Frequency Laboratories Incorporated, to render the surfaces of the material hydrophilic and the above mentioned emulsion was applied on the resulting material. The thus prepared material is hereinafter referred to as Sample C.

4. A solution consisting of 35 parts (by weight) of polystyrene, 52 parts of dimethylformamide and l3 parts of methylethylketone was prepared and this solution was coated on a stainless steel conveyor belt in the thickness of 0.3 mm and the coated layer was passed through water as it was. The film changed to a white color in the water and was then stripped from the belt, passed through water for 2 to 3 minutes and transferred into a water bath kept at 90C, in which the film was biaxially stretched nine times and dried at 70C in a roll press. Thus, a paper-like material having a specular gloss of 35 percent, an opacity of 87 percent and an average transmittance to near ultraviolet rays within the wave-length range from 320 to 450 mp. of) percent was obtained. This paper-like material was treated with a corona discharge treatment in the same manner as in the above Sample C to render the surfaces of the material hydrophilic and the above mentioned emulsion was coated on the resulting surface. The thus prepared material is hereinafter referred to as Sample D.

5. By immersing a polystyrene film having a thickness of 75 p. in a mixed solution consisting of 90 parts of methylethylketone and 10 parts of methanol at 30C for 2 seconds, thereafter casting the film on a highly polished chrome-plated plate, pressing the cast film by a roller, immersing again the film into a bath of methanol at 30C for 30 seconds to coagulate the swelled layer, followed by drying at room temperature, a paper-like material having a specular gloss of 30 percent, an opacity of 85 percent and an average transmittance to near violet rays within the wave-length range from 320 to 450 mp. was obtained. This paperlike material was treated with a corona discharge treatment in the same manner as in the above Sample to render the surface of the material hydrophilic and the above mentioned emulsion was coated on the resulting surface. The thus prepared material is hereinafter referred to as Sample E.

6. A foamed polystyrene sheet having a thickness of 500 p. was rolled by a roller at C and a support having a thickness of 200 p. and having a specular gloss of 35 percent, an opacity of 87 percent and an average transmittance to near ultraviolet rays in the wavelength range from 320 to 420 mu. of l0 percent was obtained. This support was treated with a corona discharge treatment in the same manner as in the above Sample C to render the surface of the material hydrophilic and the above mentioned silver halide emulsion was coated on the resulting surface. The thus prepared material is hereinafter referred to as Sample F.

Then on Samples A, B, C, D, E and F were respectively printed a resolving power chart by reflection printing with a Tocopebell Printer and those samples were developed with a D-72 developing solution at 20C for 1 minute and 30 seconds. After being fixed and washed, the resolving power was measured on these samples by a chart for testing the resolving power. Furthermore, these samples were used as an intermediate original for an Oripy-SOO type Printer equipped with a light source of a UM-800 type high pressure mercury lamp (800 W) manufactured by Ushio Electric Co., Ltd., printed on a diazo type lightsensitive paper by transmittanceprinting.

According to the results of the measurements, Samples C, D, E and F of the present invention showed excellent resolving powers in addition to quick transmittance printing operations for a diazo-type light sensitive paper for transmittance printing. The results of the measurements are shown in Table I.

l. By coating on a wood free paper having a thickness of 8 microns a coating composition comprising barium sulfate dispersed in a water soluble binder such as casein in a dry thickness of 15 microns, a support having a specular gloss of l 1 percent, an opacity of 82 percent and an average transmittance to near ultraviolet rays in the wave-length range from 320 to 450 mp. was obtained. On the resulting support, an ordinary gelation silver halide emulsion containing 80 ml of a 0.1 percent by weight aqueous solution of pinacryptol green, ml of a percent by weight aqueous solution of chromium alum and lml of a 10 percent by weight aqueous solution of saponin per 1 kg of the emulsion was applied at a rate of l g-Ag per square meter of the support. The resulting material is hereinafter referred to Sample G. i

g 2. By immersing a non-plasticized polyvinyl chloride resin film having a thickness of 75 microns (produced by Sanko Plastic Co.,) into a swelling bath consisting of 90 parts by weight of tetrahydrofuran and 10 parts by weight of methyl alcohol at 30C for 3 seconds to form swelled layer on both surfaces of the film, drying in the air at room temperature for 10 seconds, thereafter immersing the incompletely dried film in a coagulating bath of methyl alcohol at 25C for 1 minute, followed by drying at'room temperature, a paper-like material having a specular gloss of 38 percent. an opacity of 85 percent and an average transmittance to near ultraviolet raysin the wave-length range from 320 to 450 my" Upon the resulting material was applied the same silver halide emulsion as mentioned above. The obtained copying material is hereinafter referred to as Sample H.

3. l0 parts by weight of polyvinylchloride resin powder was dissolved in 90 parts by weight of dimethylformamide and the obtained solution was coated by a knife coating process on a stainless steel conveyor belt of a thickness of 0.4 mm and the coated layer was passed through water as it was. The film was stripped from the belt, passed through water for 2 minutes and transferred into a water bath kept at 90C, in which the film was biaxially stretched about 5 times and dried at 65C in a roll press. Thus, a paper-like material having a specular gloss of 37 percent, an opacity of 87 percent and an average transmittance to near ultraviolet rays in the wave-length range from 320 to 450 mp. of 10 percent was obtained. Upon the resulting material, the

same silver halide emulsion as mentioned above was applied. The obtained copying material is hereinafter referred to as Sample I.

Samples G, H and l were respectively measured as regards their resolving-power property by reflection printing according to the same method as stated in Example l. Furthermore, these samples were used as an intermediate original for transmittance printing of a dizao-type light sensitive paper and the printing speeds thereof were measured.

According to the results of these measurements, Samples H and l of the present invention showed excellent resolving powers and printing speeds compared to a conventional copying materiaLSample G.

These results are shown in Table 2.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

I. A copying material for photographic reflection printing and adapted to ultraviolet transmittance printing as an intermediate original, which consistsof a thermoplastic synthetic resin, paper-like support consisting of a film of thermoplastic resin and having a microporous layer on the face of and integral with said support, which microporous layer has a densified exterior surface of sufficient opaqueness and smoothness so that said support has a specular gloss on said surface of more than l0 percent measured at a specular reflection angle of 60, an opacity of to percent and an average transmittance to near ultraviolet rays within the wave-length range from 320 to 450 mg, of more than 5 percent, and a light sensitive silver halide emulconsisting of silver chloride, silver chlorobromidc. silver bromide, silver iodobromide and silver iodochlorobromide.

4. The copying material as claimed in claim 1, in which a microporous layer is formed on one or both faces of the film and the remainder of said film is free of pores. 

2. The copying material as claimed in claim 1, wherein said thermoplastic synthetic resin is selected from the group consisting of polystyrene, polyvinylchloride, polypropylene, polyethylene terephthalate and polycarbonate.
 3. The copying material as claimed in claim 1, wherein said silver halide is selected from the group consisting of silver chloride, silver chlorobromide, silver bromide, silver iodobromide and silver iodochlorobromide.
 4. The copying material as claimed in claim 1, in which a microporous layer is formed on one or both faces of the film and the remainder of said film is free of pores. 